The present invention relates generally to the field of bicycles and specifically to bicycle wheels.
Bicycle wheels commonly include an axle, a hub rotatable on the axle, spokes extending radially from the hub, a rim supported by the spokes, and a tire. Some wheels also include a pneumatic tube positioned inside the tire to facilitate inflation of the tire, while other wheels are “tubeless.” Typically, wheels can be damaged from impact by debris. Conventional wheels also are susceptible to “pinch” flats where the tire and tube are pinched between the rim and another hard object (e.g., rocks).
Existing rims often are primarily formed of metal or composite, but metal rims can easily dent when impacted and add weight to the wheel and composite rims provide poor strength and abrasion resistance and can easily crack. Other rims are formed of reinforced nylon, but these rims are also heavy and too flexible to provide adequate strength and stability. Also, some existing wheels include rims with tall tire-engaging walls to reduce pinch flats. However, these rims are heavy and typically do not adequately protect the rim from damage. Other tires place bumpers on top of the rim walls, but these bumpers are placed on top of the rim sidewalls and are typically soft (having a hardness less than 95 on the Shore A scale, or lower than 45 hardness on the Rockwell R scale) to protect the tire.